Color is imparted to textile articles by various procedures. One well-known procedure is using a high-boiling, nonionic solvent as a solvent or carrier for a dyestuff, and once applied to the fabric or textile article, heating the article to a temperature sufficient to introduce the dyestuff into the textile fibers and to fix the dyestuff in the fibers. Organic compounds capable of withstanding elevated temperatures and suited for this type of process are generally characterized as high-boiling, nonionic solvents to the extent that they solubilize or facilitate the solubilization of the dyestuff or mixtures of dyestuffs being used for the dyeing operation. In some instances, these materials have been referred to as non-aqueous, high-boiling, nonionic solvents. Illustrative of this type of solvent dyeing system are U.S. Pat. Nos. 4,115,054 to Hermes and 4,293,305 to Wilson, among others. The Wilson patent describes selected aromatic esters and cycloaliphatic diesters useful in a non-aqueous or substantially non-aqueous system including a solvent and a dyestuff and, if necessary, further additives.
While this type of solvent dyeing is extremely effective, the organic solvents used are costly and, for maximum economy, must be recycled for additional use. Further, it has been reported that inert environments serve to extend the useful life of these organic solvents, and thus a preferred manner of practicing the dyeing process is to do so in an inert atmosphere such as an atmosphere of nitrogen, Freon or other inert gas; see the published European applications of Pensa et al, EPO No. 1 159 876 and EPO No. 1 159 877.
Another patent document extolling the virtues of operating a solvent dyeing process using a high-boiling, nonionic solvent dyeing system in a non-reactive environment is U.S. Pat. No. 4,550,579 to Clifford. In this patent, the organic solvent/dyestuff dyeing composition is applied as a flowing film, termed a "microbath", so that the article being dyed is in constant contact with the dye composition. The procedure is conducted in an atmosphere that is not reactive with the organic solvent. The atmosphere is defined as any composition that can be maintained as a stable gas at the temperature of dyeing without reacting with the dye composition or textile material and that will displace air and with it oxygen surrounding the article or fabric to be dyed. Fluorocarbon solvents are preferred.
Other dyeing systems operating in a closed environment are described in U.S. Pat. No. 3,698,855 in which the flat goods to be dyed are maintained on a shelf in a closed chamber, steam is injected into the chamber and a pressurized dye liquid is sprayed onto and recirculated over the flat goods to be dyed. Similar arrangements are described in U.S. Pat. No. 3,271,102 to Morgan and U.S. Pat. No. 3,868,835 to Todd-Reeve.
None of these prior arrangements take into account the possibility of processing time sacrificed or loss of controlled environment should it become necessary to change the manner in which the dye-containing composition is applied to the textile article to be dyed. As examples, for goods dyed as a flat fabric, it may be necessary during the course of the dyeing operation to change the width of the goods and/or to change the color that the fabric is to be dyed. Particularly operating with the high-boiling, nonionic solvents, when changing from one color to the other, the operator will also use a different organic liquid in which a different color of dyestuff is dispersed. Because the dyeing operation is conducted at elevated temperatures, ranging from 350.degree. F. to as much as 450.degree. F., an attractive area in which to both apply the dye and to heat fix it to the fabric is a tenter oven. In commercial practice, these tenter ovens are of considerable size and expense, often ranging from 2 to 15 feet in width and an overall length often in excess of 100 feet. Providing a non-reactive environment to such a large piece of equipment is not only an engineering challenge, but an economic challenge as well. Supporting equipment to recover, condense and recirculate the non-reactive medium, as well as a source of additional make-up non-reactive medium, are required. Since the process may be designed to run in a continuous manner, any disruptions in the continuity of operation are costly, with respect to loss of goods being dyed. Also, when the non-reactive environment is considered, there is the expense of losing substantial quantities of the gas that is used to provide the non reactive environment. Thus, brief shut-downs for relatively minor adjustments on such equipment operated under atmospheric conditions become extremely expensive and time consuming when the equipment is operated so as to provide a non-reactive environment for the fabric being treated.
In addition to preferring a non-reactive environment for solvent dyeing using the high-boiling, nonionic solvent-based dyeing compositions, there is also a clear preference in the art to apply these compositions as a cascade, as a flowing curtain or as a thin film as opposed to simply spraying the compositions onto the goods to be dyed. Indeed, the Clifford patent, referred to above, describes at some length the disadvantages of using a spray or shower to apply the dye composition onto the textile article to be dyed. As examples, it is pointed out in this patent that a spray or shower applies the dye liquid to the textile article in the form of droplets or fine particles and this exposes the largest liquid surface to the surrounding ambient atmosphere. This means that the entire article is not in constant contact with the dye composition throughout the dyeing step, according to Clifford. There is also the possibility for significant heat loss as the droplets pass through the surrounding atmosphere before contacting the shaped article.
Despite such worrisome warnings and concerns, we have discovered and hereby disclose apparatus for accomplishing an even yet adaptable spray of high-boiling, nonionic solvent-based dye compositions to fabric in open width while it is maintained in a non-reactive environment, and which allows changes to be made in the internal components of the apparatus without discontinuing production and purging or otherwise evacuating the contents of the equipment to allow workmen to enter the equipment and adjust or repair the problem.